U.S. patent application number 16/503298 was filed with the patent office on 2020-01-23 for inductor component.
This patent application is currently assigned to Murata Manufacturing Co., Ltd.. The applicant listed for this patent is Murata Manufacturing Co., Ltd.. Invention is credited to Mizuho KATSUTA, Ryo KUDOU, Naoya NOO, Kouji YAMAUCHI, Yoshimasa YOSHIOKA.
Application Number | 20200027645 16/503298 |
Document ID | / |
Family ID | 69163242 |
Filed Date | 2020-01-23 |
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United States Patent
Application |
20200027645 |
Kind Code |
A1 |
YOSHIOKA; Yoshimasa ; et
al. |
January 23, 2020 |
INDUCTOR COMPONENT
Abstract
An inductor component comprising a first magnetic layer and a
second magnetic layer containing a resin, a substrate of a sintered
body having a first principal surface in close contact with the
first magnetic layer and a second principal surface above which the
second magnetic layer is disposed, and a spiral wiring disposed
between the second magnetic layer and the substrate.
Inventors: |
YOSHIOKA; Yoshimasa;
(Nagaokakyo-shi, JP) ; KATSUTA; Mizuho;
(Nagaokakyo-shi, JP) ; YAMAUCHI; Kouji;
(Nagaokakyo-shi, JP) ; KUDOU; Ryo;
(Nagaokakyo-shi, JP) ; NOO; Naoya;
(Nagaokakyo-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Murata Manufacturing Co., Ltd. |
Kyoto |
|
JP |
|
|
Assignee: |
Murata Manufacturing Co.,
Ltd.
Kyoto
JP
|
Family ID: |
69163242 |
Appl. No.: |
16/503298 |
Filed: |
July 3, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01F 41/122 20130101;
H01F 2017/0073 20130101; H01F 2027/2809 20130101; H01F 27/323
20130101; H01F 41/041 20130101; H01F 2017/0066 20130101; H01F
27/2804 20130101; H01F 27/255 20130101; H01F 17/0013 20130101 |
International
Class: |
H01F 27/28 20060101
H01F027/28; H01F 27/255 20060101 H01F027/255; H01F 27/32 20060101
H01F027/32; H01F 41/04 20060101 H01F041/04; H01F 41/12 20060101
H01F041/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 17, 2018 |
JP |
2018-134185 |
Claims
1. An inductor component comprising: a first magnetic layer and a
second magnetic layer containing a resin; a substrate of a sintered
body having a first principal surface in close contact with the
first magnetic layer and a second principal surface above which the
second magnetic layer is disposed; and a spiral wiring disposed
between the second magnetic layer and the substrate.
2. The inductor component according to claim 1, wherein the
substrate is a magnetic substance.
3. The inductor component according to claim 1, wherein the first
magnetic layer and the second magnetic layer contain a metal
magnetic powder contained in the resin, and wherein the substrate
is a sintered body of ferrite.
4. The inductor component according to claim 3, wherein the first
magnetic layer and the second magnetic layer further contain a
ferrite powder.
5. The inductor component according to claim 1, wherein a sum of
the thickness of the first magnetic layer and the thickness of the
second magnetic layer is larger than the thickness of the
substrate.
6. The inductor component according to claim 5, wherein the
thickness of the first magnetic layer and the thickness of the
second magnetic layer are both larger than the thickness of the
substrate.
7. The inductor component according to claim 1, wherein the
electrical resistivity of the first magnetic layer and the
electrical resistivity of the second magnetic layer are higher than
the electrical resistivity of the substrate.
8. The inductor component according to claim 1, wherein a side
surface connecting the first principal surface and the second
principal surface of the substrate is at least partially covered
with the first magnetic layer or the second magnetic layer.
9. The inductor component according to claim 1, wherein the
substrate has a crack portion.
10. The inductor component according to claim 1, further comprising
an insulating layer disposed on the second principal surface of the
substrate, wherein the spiral wiring is formed on the insulating
layer.
11. The inductor component according to claim 10, further
comprising a second insulating layer disposed on the insulating
layer, wherein the spiral wiring is covered with the second
insulating layer.
12. The inductor component according to claim 1, wherein the spiral
wiring is disposed on the second principal surface of the
substrate.
13. The inductor component according to claim 1, wherein the spiral
wiring includes a spiral-shaped first conductor layer and a second
conductor layer disposed on the first conductor layer and shaped
along the first conductor layer, and wherein the first conductor
layer has a thickness of 0.5 .mu.m or more.
14. The inductor component according to claim 1, wherein the spiral
wiring includes a spiral-shaped first conductor layer and a second
conductor layer disposed on the first conductor layer and shaped
along the first conductor layer, and wherein the first conductor
layer has a Ni content percentage of 5.0 wt % or less.
15. The inductor component according to claim 1, wherein the spiral
wiring includes a spiral-shaped first conductor layer and a second
conductor layer disposed on the first conductor layer and shaped
along the first conductor layer, and wherein a taper angle of a
side surface of the first conductor layer is larger than a taper
angle of a side surface of the second conductor layer.
16. The inductor component according to claim 1, wherein the spiral
wiring is one of a plurality of spiral wirings arranged in a
lamination direction, and wherein the plurality of spiral wirings
is connected in series.
17. The inductor component according to claim 1, wherein the spiral
wiring is one of a plurality of spiral wirings disposed on the same
plane, and wherein the spiral wirings adjacent to each other on the
same plane include side surfaces facing each other, wherein the
side surfaces are at least partially in contact with the second
magnetic layer, and wherein an insulating layer is disposed between
the spiral wirings adjacent to each other.
18. The inductor component according to claim 1, wherein the spiral
wiring includes an exposed portion exposed to the outside from a
side surface parallel to the lamination direction of the inductor
component.
19. The inductor component according to claim 18, wherein a
thickness of an exposed surface of the exposed portion is equal to
or less than the thickness of the spiral wiring and is 45 .mu.m or
more.
20. The inductor component according to claim 19, wherein the
exposed surface is an oxide film.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims benefit of priority to Japanese
Patent Application 2018-134185 filed Jul. 17, 2018, the entire
content of which is incorporated herein by reference.
BACKGROUND
Technical Field
[0002] The present disclosure relates to an inductor component.
Background Art
[0003] A conventional inductor component is described in Japanese
Laid-Open Patent Publication No. 2013-225718. This inductor
component includes an insulating substrate, a spiral conductor
formed on a principal surface of the insulating substrate, an
insulating layer containing no magnetic substance covering the
spiral conductor, an upper magnetic layer and a lower magnetic
layer covering the upper-surface side and the back-surface side of
the insulating substrate, and a pair of terminal electrodes. The
insulating substrate is a general printed circuit board material in
which a glass cloth is impregnated with epoxy resin, and the size
of the insulating substrate is 2.5 mm.times.2.0 mm.times.0.3 mm.
The upper magnetic layer and the lower magnetic layer are made of a
resin containing a metal magnetic powder.
[0004] An inductor component described in Japanese Laid-Open Patent
Publication No. 2007-305824 includes a sheet-shaped element body, a
planar coil constituting a coil formed in the element body, and a
terminal formed in an outermost circumferential portion of the
coil. The element body is a laminated body of insulating layers
using photoresist. The terminal is partially made of a magnetic
substance. A magnetic center-leg part made of a magnetic substance
is formed in an inner circumferential direction of the coil in the
element body. This inductor component is formed by laminating the
element body etc. on a substrate of silicon etc. and then removing
the substrate by a hydrofluoric acid treatment etc.
SUMMARY
[0005] In Japanese Laid-Open Patent Publication No. 2013-225718,
since the spiral conductor is formed on both surfaces of the
insulating substrate, the insulating substrate cannot be processed
after spiral conductor is formed. Therefore, if the thickness of
the insulating substrate (specifically 0.3 mm) is ensured for
stably forming a laminated object such as the spiral conductor,
this makes it difficult to reduce a height of an inductor
component, and on the other hand, if the thickness of the
insulating substrate is set such that the inductor component can be
reduced in height, this makes it difficult to stably form a
laminated object such as the spiral conductor. Therefore, it is
difficult to satisfy both the workability and the height reduction
of the inductor component.
[0006] In Japanese Laid-Open Patent Publication No. 2007-305824,
since the substrate is removed after a laminated object such as an
element body is formed on the substrate, the trade-off between the
workability and the height reduction is improved as compared to
Japanese Laid-Open Patent Publication No. 2013-225718. However, a
process of removing the substrate is likely to remove a portion of
a remaining laminated object side so as to completely eliminate the
residue of the substrate, which may cause, for example, a decrease
in strength and insulation due to partial removal of the element
body, a decrease in DC electrical resistance (Rdc) due to partial
removal of the planar coil, and a decrease in inductance (L) due to
partial removal of the magnetic material terminal and the magnetic
center-leg part. Furthermore, a removal amount on the laminated
object side may vary in each removal process at the time of mass
production, which may increase mass-production variations in the
strength, insulation, Rdc, L, component height dimension, etc.
[0007] As described above, it cannot be said that the conventional
inductor components have a configuration suitably reduced in size
and height.
[0008] Therefore, the present disclosure provides an inductor
component suitably reduced in size and height.
[0009] Accordingly, an aspect of the present disclosure provides an
inductor component comprising a first magnetic layer and a second
magnetic layer containing a resin, a substrate of a sintered body
having a first principal surface in close contact with the first
magnetic layer and a second principal surface above which the
second magnetic layer is disposed, and a spiral wiring disposed
between the second magnetic layer and the substrate.
[0010] As used herein, the phrase "in close contact" refers to a
configuration in which constituent elements are in contact with
each other without another constituent element interposed
therebetween and, for example, in the above description, refers to
a configuration in which the first principal surface of the
substrate is in direct contact with the first magnetic layer.
Additionally, the term "above" refers to a configuration in which
one of the constituent elements is located on the upper side,
including both the case that the constituent elements are in close
contact with each other as described above and the case that
another constituent element is interposed therebetween, and, for
example, in the above description, the second principal surface may
be in direct contact with the second magnetic layer or another
constituent element may be interposed between the second principal
surface and the second magnetic layer.
[0011] According to the inductor component of the present
disclosure, laminated objects such as the second magnetic layer and
the spiral wiring above the second principal surface can be formed
on the second principal surface of the stable substrate that is a
sintered body, and therefore, the formation accuracy of the
laminated objects can be improved. Since the first principal
surface of the substrate is in close contact with the first
magnetic layer, the spiral wiring is not formed on the first
principal surface. Therefore, even if the thickness of the
substrate is ensured to some extent so as to improve the formation
accuracy of the laminated objects, the substrate can be processed
by polishing etc. from the first principal surface side, so that
the thickness can be reduced after the laminated objects are formed
on the second principal surface. Therefore, both the formation
accuracy and the height reduction of the inductor component can be
achieved.
[0012] Additionally, since the substrate is not completely removed,
the laminated objects such as the spiral wiring can be protected
from the processing, and mass-production variations in Rdc etc. can
be suppressed.
[0013] Furthermore, by adding a processing amount of the substrate
as an adjustment element to a manufacturing process, a degree of
design freedom can be improved in terms of the strength, L, height
dimension, etc. of the inductor component, and the mass-production
variations thereof can be reduced.
[0014] The spiral wiring means a curve (two-dimensional curve)
extending on a plane, may be a curve having the number of turns
exceeding one or may be a curve having the number of turns less
than one, or may have a portion that is a straight line.
[0015] In an embodiment of the inductor component, the substrate is
a magnetic substance. According to the embodiment, a region of the
magnetic substance is increased in the inductor component, so that
L can be improved.
[0016] In an embodiment of the inductor component, the first
magnetic layer and the second magnetic layer contain a metal
magnetic powder contained in the resin, and the substrate is a
sintered body of ferrite. According to the embodiment, DC
superimposition characteristics can be improved by the first
magnetic layer and the second magnetic layer containing the metal
magnetic powder.
[0017] In an embodiment of the inductor component, the first
magnetic layer and the second magnetic layer further contain a
ferrite powder. According to the embodiment, the effective magnetic
permeability, i.e., the magnetic permeability per volume of the
first and second magnetic layers, can be improved by containing the
ferrite having a high relative magnetic permeability.
[0018] In an embodiment of the inductor component, a sum of the
thickness of the first magnetic layer and the thickness of the
second magnetic layer is larger than the thickness of the
substrate. According to the embodiment, since the proportion of the
magnetic layers containing a resin becomes large, the stress
absorbability of the inductor component is improved, and the
reliability is improved. Additionally, if the first magnetic layer
and second magnetic layer contain the metal magnetic powder, the DC
superimposition characteristics of the inductor component can be
improved.
[0019] In an embodiment of the inductor component, the thickness of
the first magnetic layer and the thickness of the second magnetic
layer are both larger than the thickness of the substrate.
According to the embodiment, since the proportion of the magnetic
layers containing a resin becomes larger, the stress absorbability
of the inductor component is further improved, and the reliability
is further improved. Additionally, if the first magnetic layer and
second magnetic layer contain the metal magnetic powder, the DC
superimposition characteristics of the inductor component can
further be improved.
[0020] In an embodiment of the inductor component, the electrical
resistivity of the first magnetic layer and the electrical
resistivity of the second magnetic layer are higher than the
electrical resistivity of the substrate. According to the
embodiment, an iron loss, i.e., a loss due to a material, can be
reduced by including a portion having a high electrical
resistivity. In the above description, the electrical resistivities
of the first magnetic layer, the second magnetic layer, and the
substrate are based on the product of an electrical resistance per
unit length at 1.0 V and a cross-sectional area.
[0021] In an embodiment of the inductor component, a side surface
connecting the first principal surface and the second principal
surface of the substrate is at least partially covered with the
first magnetic layer or the second magnetic layer. According to the
embodiment, since the proportion of the magnetic layers containing
a resin becomes larger, the stress absorbability of the inductor
component is improved, and the reliability is improved.
Additionally, if the first magnetic layer and second magnetic layer
contain the metal magnetic powder, the DC superimposition
characteristics of the inductor component can be improved.
[0022] In an embodiment of the inductor component, the substrate
has a crack portion. According to the embodiment, a stress is
released in the crack portion, and the impact resistance of the
inductor component is improved.
[0023] In an embodiment of the inductor component, the inductor
component further comprises an insulating layer disposed on the
second principal surface of the substrate, and the spiral wiring is
formed on the insulating layer. According to the embodiment, the
insulation of the spiral wiring is improved.
[0024] In an embodiment of the inductor component, the inductor
component further comprises a second insulating layer disposed on
the insulating layer, and the spiral wiring is covered with the
second insulating layer. According to the embodiment, the
insulation of the spiral wiring is further improved. The insulating
layer and the second insulating layer may be integrated.
[0025] In an embodiment of the inductor component, the spiral
wiring is disposed on the second principal surface of the
substrate. According to the embodiment, since no other constituent
element such as the insulating layer is interposed between the
spiral wiring and the second principal surface of the substrate,
the characteristics such as L and Rdc can be improved in the same
volume or the height can be reduced while maintaining the same
characteristics.
[0026] In an embodiment of the inductor component, the spiral
wiring includes a spiral-shaped first conductor layer and a second
conductor layer disposed on the first conductor layer and shaped
along the first conductor layer, and the first conductor layer has
a thickness of 0.5 .mu.m or more. According to the embodiment, the
unevenness of the substrate can be absorbed by the thickness of the
first conductor layer, and the formation and processing of the
second conductor layer is facilitated, so that the formation
accuracy of the inductor component is improved.
[0027] In an embodiment of the inductor component, the spiral
wiring includes a spiral-shaped first conductor layer and a second
conductor layer disposed on the first conductor layer and shaped
along the first conductor layer, and the first conductor layer has
a Ni content percentage of 5.0 wt % or less. According to the
embodiment, a difference can be reduced between the electric
conductivity of the first conductor layer and the electric
conductivity of the second conductor layer, and the current flowing
through the spiral wiring flows substantially uniformly in cross
sections of the first conductor layer and the second conductor
layer, so that heat generation can be made uniform in the spiral
wiring. Additionally, Rdc of the spiral wiring is reduced.
[0028] In an embodiment of the inductor component, the spiral
wiring includes a spiral-shaped first conductor layer and a second
conductor layer disposed on the first conductor layer and shaped
along the first conductor layer, and a taper angle of a side
surface of the first conductor layer is larger than a taper angle
of a side surface of the second conductor layer. According to the
embodiment, the filling property of the second magnetic layer is
improved on the side surface of the spiral wiring.
[0029] In an embodiment of the inductor component, the spiral
wiring is one of a plurality of spiral wirings arranged in a
lamination direction, and the plurality of spiral wirings is
connected in series. According to the embodiment, L can be
improved.
[0030] In an embodiment of the inductor component, the spiral
wiring is one of a plurality of spiral wirings disposed on the same
plane, and the spiral wirings adjacent to each other on the same
plane include side surfaces facing each other. The side surfaces
are at least partially in contact with the second magnetic layer,
and an insulating layer is disposed between the spiral wirings
adjacent to each other. According to the embodiment, the insulation
and voltage resistance between the adjacent spiral wirings are
improved.
[0031] In an embodiment of the inductor component, the spiral
wiring includes an exposed portion exposed to the outside from a
side surface parallel to the lamination direction of the inductor
component. According to the embodiment, since the spiral wiring
includes the exposed portion, a resistance to electrostatic
destruction can be improved at the time of manufacturing.
[0032] In an embodiment of the inductor component, a thickness of
an exposed surface of the exposed portion is equal to or less than
the thickness of the spiral wiring and is 45 .mu.m or more.
According to the embodiment, since the thickness of the exposed
surface is equal to or less than the thickness of the spiral
wirings, the proportion of the magnetic layers can be increased,
and L can be improved. Additionally, since the thickness of the
exposed surface is 45 .mu.m or more, occurrence of disconnection
can be reduced.
[0033] In an embodiment of the inductor component, the exposed
surface is an oxide film. According to the embodiment, a short
circuit can be suppressed between the inductor component and the
adjacent component.
[0034] According to the inductor component of an aspect of the
present disclosure, the inductor component suitably reduced in size
and height can be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1A is a transparent plan view showing an inductor
component according to a first embodiment;
[0036] FIG. 1B is a cross-sectional view showing the inductor
component according to the first embodiment;
[0037] FIG. 2 is an enlarged cross-sectional view showing a
preferable form of a spiral wiring;
[0038] FIG. 3A is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0039] FIG. 3B is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0040] FIG. 3C is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0041] FIG. 3D is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0042] FIG. 3E is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0043] FIG. 3F is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0044] FIG. 3G is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0045] FIG. 3H is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0046] FIG. 3I is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0047] FIG. 3J is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0048] FIG. 3K is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0049] FIG. 3L is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0050] FIG. 3M is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0051] FIG. 3N is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0052] FIG. 3O is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0053] FIG. 3P is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0054] FIG. 3Q is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0055] FIG. 3R is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0056] FIG. 3S is an explanatory view for explaining a
manufacturing method of the inductor component according to the
first embodiment;
[0057] FIG. 4 is a cross-sectional view showing an inductor
component according to a second embodiment;
[0058] FIG. 5A is a transparent plan view showing an inductor
component according to a third embodiment;
[0059] FIG. 5B is a cross-sectional view showing an inductor
component according to the third embodiment;
[0060] FIG. 6A is a transparent plan view showing an inductor
component according to a fourth embodiment;
[0061] FIG. 6B is a cross-sectional view showing an inductor
component according to the fourth embodiment;
[0062] FIG. 7A is a transparent plan view showing an inductor
component according to a fifth embodiment; and
[0063] FIG. 7B is a cross-sectional view showing an inductor
component according to the fifth embodiment.
DETAILED DESCRIPTION
[0064] An inductor component of an aspect of the present disclosure
will now be described in detail with reference to shown
embodiments. The drawings include schematics and may not reflect
actual dimensions or ratios.
First Embodiment
(Configuration)
[0065] FIG. 1A is a transparent plan view showing a first
embodiment of an inductor component. FIG. 1B is a cross-sectional
view taken along a line X-X of FIG. 1A.
[0066] An inductor component 1 is mounted on an electronic device
such as a personal computer, a DVD player, a digital camera, a TV,
a portable telephone, a smartphone, and automotive electronics, for
example, and is a component generally having a rectangular
parallelepiped shape, for example. However, the shape of the
inductor component 1 is not particularly limited and may be a
circular columnar shape, a polygonal columnar shape, a truncated
cone shape, or a truncated polygonal pyramid shape.
[0067] As shown in FIGS. 1A and 1B, the inductor component 1 has a
substrate 61, a first magnetic layer 11, a second magnetic layer
12, an insulating layer 15, a spiral wiring 21, vertical wirings
51, 52, external terminals 41, 42, and a coating film 50.
[0068] The substrate 61 has a flat plate shape and is a portion
serving as a base for a manufacturing process of the inductor
component 1. The substrate 61 includes a first principal surface
61a as a lower surface and a second principal surface 61b as an
upper surface. A normal direction relative to the principal
surfaces 61a, 61b is defined as a Z direction (up-down direction)
in the figures, and in the following description, it is assumed
that a forward Z direction faces toward the upper side while a
reverse Z direction faces toward the lower side. The Z direction is
the same in the other embodiments and examples.
[0069] The substrate 61 is polished on the first principal surface
61a side, and the thickness of the substrate 61 is 5 .mu.m or more
and 100 .mu.m or less (i.e., from 5 .mu.m to 100 .mu.m), for
example. For example, the substrate 61 is preferably a sintered
body of a magnetic substrate made of NiZn- or MnZn-based ferrite or
a nonmagnetic substrate made of alumina or glass. As a result, the
strength and flatness of the substrate 61 can be ensured, and a
workability of a laminated object on the substrate 61 is
improved.
[0070] The spiral wiring 21 is formed only on the upper side of the
substrate 61, or specifically, on the insulating layer 15 on the
second principal surface 61b of the substrate 61 and is a wiring
extending in a spiral shape along the second principal surface 61b
of the substrate 61. The spiral wiring 21 has a spiral shape with
the number of turns exceeding one. The spiral wiring 21 is spirally
wound in a clockwise direction from an outer circumferential end
21b toward an inner circumferential end 21a when viewed from the
upper side, for example.
[0071] The thickness of the spiral wiring 21 is preferably 40 .mu.m
or more and 120 .mu.m or less, for example. An example of the
spiral wiring 21 has a thickness of 45 .mu.m, a wiring width of 50
.mu.m, and an inter-wiring space of 10 .mu.m. The inter-wiring
space is preferably 3 .mu.m or more and 20 .mu.m or less (i.e.,
from 3 .mu.m to 20 .mu.m).
[0072] The spiral wiring 21 is made of a conductive material and is
made of a metal material having a low electric resistance such as
Cu, Ag, and Au, for example. In this embodiment, the inductor
component 1 includes only one layer of the spiral wiring 21, so
that the inductor component 1 can be reduced in height.
Specifically, the spiral wiring 21 has both ends (the inner
circumferential end 21a and the outer circumferential end 21b)
provided with pad portions having a line width slightly larger than
a spiral-shaped portion and is directly connected at the pad
portions to the vertical wirings 51, 52.
[0073] The insulating layer 15 is a film-shaped layer formed on the
second principal surface 61b of the substrate 61 and covers the
spiral wiring 21. Specifically, the insulating layer 15 entirely
covers bottom and side surfaces of the spiral wiring 21 and covers
an upper surface of the spiral wiring 21 in portions other than
connecting portions to via conductors 25. The insulating layer 15
has a hole portion at a position corresponding to an inner
circumferential portion of the spiral wiring 21. The thickness of
the insulating layer 15 between the substrate 61 and the bottom
surface of the spiral wiring 21 is 10 .mu.m or less, for
example.
[0074] The insulating layer 15 is made of an insulating material
containing no magnetic substance and is made of, for example, a
resin material such as an epoxy resin, a phenol resin, a polyimide
resin. The insulating layer 15 may contain a filler of a
nonmagnetic substance such as silica and, in this case, the
insulating layer 15 can be improved in the strength, workability,
and electrical characteristics.
[0075] The first magnetic layer 11 is in close contact with the
first principal surface 61a of the substrate 61. The second
magnetic layer 12 is disposed above the second principal surface
61b of the substrate 61. The spiral wiring 21 is disposed between
the second magnetic layer 12 and the substrate 61. In this
embodiment, the second magnetic layer 12 is formed along the
insulating layer 15 to cover not only the upper side of the spiral
wiring 21 but also the inner and outer circumferential portions of
the spiral wiring 21.
[0076] The first magnetic layer 11 and the second magnetic layer 12
contain a resin containing a powder of a magnetic material. The
resin is, for example, an epoxy resin, a phenol resin, a polyimide
resin, an acrylic resin, a phenol resin, a vinyl ether resin, and a
mixture thereof. The powder of the magnetic material is, for
example, a powder of metal magnetic material including an FeSi
alloy such as FeSiCr, an FeCo alloy, an Fe alloy such as NiFe, or
an amorphous alloy thereof, or a powder of NiZn- or MnZn-based
ferrite etc. The content percentage of the magnetic material is
preferably 50 vol % or more and 85 vol % or less (i.e., from 50 vol
% to 85 vol %) relative to the whole magnetic layer. The powder of
the magnetic material preferably has particles of substantially
spherical shape, and the average particle diameter is preferably 5
.mu.m or less. The resin constituting the first and second magnetic
layers 11, 12 is preferably the same type of material as the
insulating layer 15, and in this case, the adhesion between the
insulating layer 15 and the first and second magnetic layers 11, 12
can be improved.
[0077] The vertical wirings 51, 52 are made of a conductive
material, extend from the spiral wiring 21 in the Z direction, and
penetrate the inside of the second magnetic layer 12. The vertical
wirings 51, 52 include the via conductors 25 extending from the
spiral wiring 21 in the Z direction and penetrating the inside of
the insulating layer 15 and columnar wirings 31, 32 extending from
the via conductors 25 and penetrating the inside of the second
magnetic layer 12.
[0078] The first vertical wiring 51 includes the via conductor 25
extending upward from the upper surface of the inner
circumferential end 21a of the spiral wiring 21 and the first
columnar wiring 31 extending upward from the via conductor 25 and
penetrating the inside of the first magnetic layer 11. The second
vertical wiring 52 includes the via conductor 25 extending upward
from the upper surface of the outer circumferential end 21b of the
spiral wiring 21 and the second columnar wiring 31 extending upward
from the via conductor 25 and penetrating the inside of the first
magnetic layer 11. The vertical wirings 51, 52 are made of the same
material as the spiral wiring 21.
[0079] The external terminals 41, 42 are made of a conductive
material and has, for example, a three-layer configuration with Cu
having low electric resistance and excellent in stress resistance,
Ni excellent in corrosion resistance, and Au excellent in solder
wettability and reliability arranged in this order from the inside
to the outside.
[0080] The first external terminal 41 is disposed on the upper
surface of the second magnetic layer 12 and covers an end surface
of the first columnar wiring 31 exposed from the upper surface. As
a result, the first external terminal 41 is electrically connected
to the inner circumferential end 21a of the spiral wiring 21. The
second external terminal 42 is disposed on the upper surface of the
second magnetic layer 12 and covers an end surface of the second
columnar wiring 32 exposed from the upper surface. As a result, the
second external terminal 42 is electrically connected to the outer
circumferential end 21b of the spiral wiring 21.
[0081] Preferably, a rust prevention treatment is applied to the
external terminals 41, 42. This rust prevention treatment refers to
coating with Ni and Au, or Ni and Sn, etc. This enables the
suppression of copper leaching due to solder and the rusting so
that the inductor component 1 with high mounting reliability can be
provided.
[0082] The coating film 50 is made of an insulating material and
covers the upper surface of the second magnetic layer 12 to expose
the end surfaces of the columnar wirings 31, 32 and the external
terminals 41, 42. With the coating film 50, the insulation of the
surface of the inductor component 1 can be ensured. The coating
film 50 may be formed on the lower surface side of the first
magnetic layer 11.
[0083] According to the inductor component 1, laminated objects
such as the second magnetic layer 12 and the spiral wiring 21 above
the second principal surface 61b can be formed on the second
principal surface 61b of the stable substrate 61 that is a sintered
body, and therefore, the formation accuracy of the laminated
objects can be improved. Since the first principal surface 61a is
in close contact with the first magnetic layer 11, the spiral
wiring 21 is not formed on the first principal surface 61a. As a
result, even if the thickness of the substrate 61 is ensured to
some extent so as to improve the formation accuracy of the
laminated objects, the substrate 61 can be processed by polishing
etc. from the first principal surface 61a side, so that the
thickness can be reduced after the laminated objects are formed on
the second principal surface 61b. Therefore, both the formation
accuracy and the height reduction of the inductor component 1 can
be achieved.
[0084] Additionally, since the substrate 61 is not completely
removed, the laminated objects such as the spiral wiring 21, the
second magnetic layer 12, and the insulating layer 15 can be
protected from the processing, and mass-production variations in
Rdc etc. can be suppressed.
[0085] Furthermore, by adding a processing amount of the substrate
61 as an adjustment element to a manufacturing process, a degree of
design freedom can be improved in terms of the strength, L, height
dimension, etc. of the inductor component 1, and the
mass-production variations thereof can be reduced.
[0086] The insulating layer 15 is directly disposed on the second
principal surface 61b of the substrate 61, and the spiral wiring 21
is formed on the insulating layer 15. As a result, the insulating
layer 15 is interposed between the spiral wiring 21 and the second
principal surface 61b, so that the insulation of the spiral wiring
21 is improved on the second principal surface 61b side.
[0087] The spiral wiring 21 is covered with the insulating layer
15. As a result, the spiral wiring 21 is covered with the
insulating layer 15, and the insulation of the spiral wiring 21 is
further improved. In this embodiment, the insulating layer 15 with
the spiral wiring 21 formed thereon and the insulating layer 15
covering the spiral wiring 21 are integrated; however, for example,
a second insulating layer covering the spiral wiring 21 may further
be included separately from the insulating layer with the spiral
wiring 21 formed thereon.
[0088] Preferably, the substrate 61 is a magnetic substance. As a
result, a region of the magnetic substance is increased in the
inductor component 1, so that L can be improved.
[0089] Preferably, the first and second magnetic layers 11, 12
contain a metal magnetic powder contained in a resin, and the
substrate 61 is a sintered body of ferrite. As a result, DC
superimposition characteristics can be improved by the first
magnetic layer 11 and the second magnetic layer 12 containing the
metal magnetic powder.
[0090] Preferably, the first and second magnetic layers 11, 12
further contain a ferrite powder. As a result, the effective
magnetic permeability, i.e., the magnetic permeability per volume
of the first and second magnetic layers 11, 12, can be improved by
containing not only the metal magnetic powder but also the ferrite
having a high relative magnetic permeability.
[0091] Preferably, the sum of the thickness of the first magnetic
layer 11 and the thickness of the second magnetic layer 12 is
larger than the thickness of the substrate 61. In other words, the
sum of the volume of the first magnetic layer 11 and the volume of
the second magnetic layer 12 is larger than the volume of the
substrate 61. As a result, since the proportion of the magnetic
layers 11, 12 containing a relatively soft resin becomes large, the
stress absorbability of the inductor component 1 is improved, and
an influence of thermal shock, external pressure, etc. can be
reduced, so that the reliability of the inductor component 1 is
improved. Additionally, if the first and second magnetic layers 11,
12 contain the metal magnetic powder, the DC superimposition
characteristics of the inductor component 1 can be improved.
[0092] Preferably, the thickness of the first magnetic layer 11 and
the thickness of the second magnetic layer 12 are both greater than
the thickness of the substrate 61. As a result, since the
proportion of the magnetic layers 11, 12 containing a relatively
soft resin becomes larger, the stress absorbability of the inductor
component 1 is further improved, and an influence of thermal shock,
external pressure, etc. can be reduced, so that the reliability of
the inductor component 1 is further improved. Additionally, if the
first and second magnetic layers 11, 12 contain the metal magnetic
powder, the DC superimposition characteristics of the inductor
component 1 can further be improved.
[0093] Preferably, the electrical resistivity of the first magnetic
layer 11 and the electrical resistivity of the second magnetic
layer 12 are higher than the electrical resistivity of the
substrate 61. As a result, an iron loss, i.e., a loss due to a
material, can be reduced by including a portion having a high
electrical resistivity.
[0094] Specifically, a method of measuring the electrical
resistivity in the present application may include: forming an
electrode of a gallium-indium alloy on an object to be measured
taken out by polishing or cutting; measuring an electrical
resistance at an applied voltage of 1.0 V at room temperature by
using an insulation resistance meter; and making a calculation
based on a formed electrode area and an interelectrode distance
with the following equation: electrical resistivity
(.OMEGA.m)=electrical resistance (.OMEGA.).times.(electrode area
(m.sup.2)/interelectrode distance (m). An object to be measured in
a material state may be hardened by applying pressure, heat, etc.,
before measurement. For example, the electrical resistivity of the
first magnetic layer 11 and the second magnetic layer 12 is on the
order of 1.0.times.10.sup.11 to 12 .OMEGA.m, and the electrical
resistivity of the substrate 61 is on the order of
1.0.times.10.sup.9 to 10 .OMEGA.m.
[0095] Preferably, the substrate 61 has a crack portion. The crack
portion is formed by fracture inside the substrate 61. As a result,
a stress is released in the crack portion, and the impact
resistance of the inductor component 1 is improved.
[0096] Preferably, the spiral wiring 21 has a spiral-shaped first
conductor layer, and a second conductor layer disposed on the first
conductor layer and shaped along the first conductor layer, and the
thickness of the first conductor layer is 0.5 .mu.m or more. As a
result, the unevenness of the substrate 61 can be absorbed by the
thickness of the first conductor layer, and the formation and
processing of the second conductor layer are facilitated, so that
the formation accuracy of the inductor component 1 is improved.
[0097] Preferably, the spiral wiring 21 has a spiral-shaped first
conductor layer and a second conductor layer disposed on the first
conductor layer and shaped along the first conductor layer, and the
Ni content percentage of the first conductor layer is 5.0 wt % or
less. As a result, a difference can be reduced between the electric
conductivity of the first conductor layer and the electric
conductivity of the second conductor layer, and the current flowing
through the spiral wiring 21 flows substantially uniformly in cross
sections of the first conductor layer and the second conductor
layer, so that heat generation can be made uniform in the spiral
wiring 21. Additionally, Rdc of the spiral wiring 21 is reduced. In
this case, it can be said that a first conductor layer 211 is not
formed by electroless plating.
[0098] As described above, if the first conductor layer is not
formed by electroless plating, the first magnetic layer 11 can be
prevented from being affected by a process of applying a catalyst
to the first magnetic layer 11, an electroless plating process (a
seed layer forming step), and a process of etching a conductor
layer formed by electroless plating (a seed layer removing step).
Specifically, the first magnetic layer 11 contains a magnetic
powder, and the magnetic powder can be restrained from being
removed by a plating solution, an etching solution, etc. used in a
pretreatment or a process at the time of formation of the first
conductor layer. Therefore, as described above, if the first
conductor layer has a feature that the layer is not formed by
electroless plating, the first magnetic layer 11 can be prevented
from decreasing in magnetic permeability and decreasing in
strength.
[0099] In a method of measuring the Ni content percentage, after
performing a pretreatment for making a boundary between the first
conductor layer and the second conductor layer clear as needed, the
Ni content percentage (wt %) on the first conductor layer side is
calculated by performing EDX analysis with a scanning transmission
electron microscope (STEM). Regarding the pretreatment, for
example, a wiring having the first conductor layer and the second
conductor layer may be exposed on a cross section by polishing or
milling, and the cross section may thinly be etched by dry etching
with Ar or wet etching with nitric acid so that the boundary
between the first conductor layer and the second conductor layer
thereby becomes clearer due to a difference in etching rate.
However, regardless of the presence/absence of the pretreatment,
the first conductor layer may be determined from a continuity and a
particle size of particles by STEM. The EDX analysis may be
performed by using, for example, JEM-2200FS manufactured by JEOL as
STEM and Noran System 7 manufactured by Thermo Fisher Scientific as
an EDX system at the magnification of 400 k (magnification of 400 k
or more as needed).
[0100] Preferably, as shown in FIG. 2, the spiral wiring 21 has the
spiral-shaped first conductor layer 211 and a second conductor
layer 212 disposed on the first conductor layer 211 and shaped
along the first conductor layer 211. A taper angle of a side
surface 211a of the first conductor layer 211 is larger than a
taper angle of a side surface 212a of the second conductor layer
212. The side surface 211a of the first conductor layer 211 refers
to a surface in the width direction of the first conductor layer
211, and the side surface 212a of the second conductor layer 212
refers to a surface in the width direction of the second conductor
layer 212. As a result, the spiral wiring 21 is forward tapered so
that the second magnetic layer 12 can easily be filled between
wirings of the spiral wiring 21.
[0101] For example, the taper angle of the side surface 211a of the
first conductor layer 211 is 30.0.degree., and the taper angle of
the side surface 212a of the second conductor layer 212 is
1.2.degree.. In this case, based on the Z direction (0.degree.),
the angle is positive when a taper shape is formed, and the angle
is negative when a reverse taper shape is formed. The taper angle
may accurately be measured in a region of 80% excluding upper/lower
20% of the thickness of each of the first conductor layer 211 and
the second conductor layer 212.
[0102] Preferably, the line width of the first conductor layer 211
is different from the line width of the second conductor layer 212.
The line width of the first conductor layer 211 refers to the
maximum value of the width of the first conductor layer 211, and
the line width of the second conductor layer 212 refers to the
maximum value of the width of the second conductor layer 212. As a
result, a combination of formation methods of conductor layers
forming various shapes can be employed, which increases a degree of
design freedom of the spiral wiring 21.
[0103] The line width of the first conductor layer 211 is
preferably larger than the line width of the second conductor layer
212 and, as a result, the spiral wiring 21 has a forward tapered
shape widened on the bottom surface side and narrowed on the top
side, so that the second magnetic layer 12 is easily filled in the
vicinity of the side surfaces of the spiral wiring 21.
[0104] The present disclosure is not limited to the relationships
of the line width and the taper angle of FIG. 2 and, for example,
the line width or the taper angle of the first conductor layer 211
may be smaller than the line width or taper angle of the second
conductor layer 212.
[0105] The substrate 61 may be provided with a hole portion at a
position corresponding to the inner circumferential portion of the
spiral wiring 21 so that either or both of the first magnetic layer
11 and the second magnetic layer 12 can be disposed in the hole
portion of the substrate 61, and since an increase in proportion of
the first and second magnetic layers 11, 12 containing the
relatively soft resin improves the stress absorbability of the
inductor component 1 so that the influence of thermal shock,
external pressure, etc. can be reduced, the reliability of the
inductor component 1 can be improved. Additionally, if the first
magnetic layer 11 and the second magnetic layer 12 contain the
metal magnetic powder, the DC superimposition characteristics of
the inductor component 1 can be improved.
[0106] The substrate 61 may have a shape along the spiral shape of
the spiral wiring 21, and since a reduction in proportion of the
substrate 61 in the inductor component 1 increases the proportion
of the first and second magnetic layers 11, 12 containing the
relatively soft resin, the stress absorbability of the inductor
component 1 is improved so that the influence of thermal shock,
external pressure, etc. can be reduced, and therefore, the
reliability of the inductor component 1 can be improved.
Additionally, if the first magnetic layer 11 and the second
magnetic layer 12 contain the metal magnetic powder, the DC
superimposition characteristics of the inductor component 1 can be
improved.
[0107] A vertical wiring may be disposed such that the wiring is
led out from the spiral wiring 21 to the lower surface of the
inductor component 1. In this case, an external terminal connected
to the vertical wiring may be disposed on the lower surface of the
inductor component 1. This can improve a degree of freedom of
connection between the inductor component 1 and another circuit
component.
[0108] Although the inductor component 1 has the one spiral wiring
21, the present disclosure is not limited to this configuration,
and the inductor component 1 may include two or more spiral wirings
wound on the same plane. Since the inductor component 1 has a high
degree of freedom in terms of formation of external terminals, the
effect thereof is more prominent in the inductor component having a
larger number of external terminals.
(Manufacturing Method)
[0109] A manufacturing method of the inductor component 1 will be
described.
[0110] As shown in FIG. 3A, the substrate 61 is prepared. The
substrate 61 is a flat plate-shaped substrate made of sintered
ferrite, for example. Since the thickness of the substrate 61 does
not affect the thickness of the inductor component, the substrate
with easy-to-handle thickness may appropriately be used for the
reason of warpage due to processing etc.
[0111] As shown in FIG. 3B, an insulating layer 62 containing no
magnetic substance is formed on the substrate 61. The insulating
layer 62 is made of, for example, a polyimide resin containing no
magnetic substance and is formed by coating with the polyimide
resin on the upper surface (the second principal surface 61b) of
the substrate 61 by printing, application, etc. The insulating
layer 62 may be formed as a thin film of an inorganic material such
as a silicon oxide film by a dry process such as vapor deposition,
sputtering, and CVD on the upper surface of the substrate 61, for
example.
[0112] As shown in FIG. 3C, the insulating layer 62 is patterned by
photolithography to leave a region for forming the spiral wiring.
Specifically, the insulating layer 62 is removed while leaving a
portion along the spiral wiring. The insulating layer 62 is
provided with an opening 62a through which the substrate 61 is
exposed. As shown in FIG. 3D, a seed layer 63 of Cu is formed on
the substrate 61 including the insulating layer 62 by sputtering,
electroless plating, etc. The seed layer 63 may be formed on
another substrate by electrolytic plating and transferred to the
substrate 61.
[0113] As shown in FIG. 3E, a dry film resist (DFR) 64 is affixed
onto the seed layer 63. As shown in FIG. 3F, the DFR 64 is
patterned by photolithography to form a through-hole 64a in a
region for forming the spiral wiring 21, so that the seed layer 63
is exposed from the through-hole 64a.
[0114] As shown in FIG. 3G, a metal film 65 is formed on the seed
layer 63 in the through-hole 64a by electroplating. As shown in
FIG. 3H, after formation of the metal film 65, the DFR 64 is
removed, and the seed layer 63 is removed by etching in an exposed
portion on which the metal film 65 is not formed. As a result, the
spiral wiring 21 is formed, and a sacrificial conductor layer 66 is
formed at a position corresponding to the inner circumferential
portion and the outer circumferential portion of the spiral wiring
21.
[0115] As shown in FIG. 3I, the insulating layer 62 is further
formed, and as in FIG. 3C, the insulating layer 62 is removed in a
region overlapping with the inner circumferential portion and the
outer circumferential portion of the spiral wiring 21. As shown in
FIG. 3J, the sacrificial conductor layer 66 is removed.
Subsequently, in this case, the insulating layers 62 on both end
portions of the spiral wiring 21 are also removed. As a result, the
spiral wiring 21 is covered with the insulating layer 15
(insulating layer 62). Therefore, the spiral wiring 21 has the seed
layer 63 as the first conductor layer and the metal film 65 as the
second conductor layer. The metal film 65 has a spiral shape along
the seed layer 63.
[0116] As shown in FIG. 3K, the via conductors 25 and the first and
second columnar wirings 31, 32 are formed as in FIGS. 3D to 3H. As
a result, the first and second vertical wirings 51, 52 are
formed.
[0117] As shown in FIG. 3L, a magnetic sheet 67 made of a magnetic
material is pressure-bonded to the upper-surface side (spiral
wiring formation side) of the substrate 61. As a result, the second
magnetic layer 12 is formed on the second principal surface 61b
side of the substrate 61.
[0118] As shown in FIG. 3M, the magnetic sheet 67 is polished to
expose upper ends of the vertical wirings 51, 52 (the columnar
wirings 31, 32. As shown in FIG. 3N, a solder resist (SR) 68 is
formed as the coating film 50 on the upper surface of the magnetic
sheet 67.
[0119] As shown in FIG. 3O, the SR 68 is patterned by
photolithography to form through-holes 68a through which the first
and second vertical wirings 51, 52 and the second magnetic layer 12
(the magnetic sheet 67) are exposed, in a region for forming
external terminals.
[0120] As shown in FIG. 3P, the substrate 61 is polished from the
first principal surface 61a side. In this case, the substrate 61 is
not completely removed and is partially left. As shown in FIG. 3Q,
the magnetic sheet 67 made of a magnetic material is
pressure-bonded to the first principal surface 61a on the polished
side of the substrate 61 and is polished to an appropriate
thickness.
[0121] As shown in FIG. 3R, a metal film 69 of Cu/Ni/Au is formed
by electroless plating and grown from the vertical wirings 51, 52
into the through-holes 68a of the SR 68. The metal film 69 forms
the first external terminal 41 connected to the first vertical
wiring 51 and the second external terminal 42 connected to the
second vertical wiring 52. As shown in FIG. 3S, individual pieces
are formed and subjected to barrel polishing as needed, and burrs
are removed to manufacture the inductor component 1.
[0122] The manufacturing method of the inductor component 1 is
merely an example, and techniques and materials used in steps may
appropriately be replaced with other known techniques and
materials. For example, although the insulating layer 62, the DFR
64, and the SR 68 are patterned after coating in the above
description, the insulating layer 62 may directly be formed on
necessary portions by application, printing, mask vapor deposition,
lift-off, etc. Although polishing is used for removal of the
substrate 61 and thinning of the magnetic sheet 67, another
physical process such as blasting and laser or a chemical process
such as hydrofluoric acid treatment may be used.
Second Embodiment
[0123] FIG. 4 is a cross-sectional view showing a second embodiment
of an inductor component. The second embodiment is different from
the first embodiment in configuration of the insulating layer and
the magnetic layer. This different configuration will hereinafter
be described. The other constituent elements have the same
configuration as the first embodiment and are denoted by the same
reference numerals as the first embodiment and will not be
described.
[0124] As shown in FIG. 4, as compared to the inductor component 1
of the first embodiment, an inductor component 1A of the second
embodiment does not include the insulating layer 15 of the first
embodiment, and the substrate 61 is covered with the magnetic
layers 11, 12.
[0125] Specifically, a side surface 61c connecting the first
principal surface 61a and the second principal surface 61b of the
substrate 61 is covered with the first magnetic layer 11 or the
second magnetic layer 12. As a result, since the proportion of the
magnetic layers 11, 12 containing a relatively soft resin becomes
larger, the stress absorbability of the inductor component 1A is
improved, and an influence of thermal shock, external pressure,
etc. can be reduced, so that the reliability of the inductor
component 1A is improved. Additionally, when if the magnetic layers
11, 12 contain the metal magnetic powder, the DC superimposition
characteristics of the inductor component 1A can be improved. The
side surface 61c may entirely be covered by the magnetic layers 11,
12, or the side surface 61c may at least partially be covered with
the magnetic layers 11, 12.
[0126] The spiral wiring 21 is directly disposed on the second
principal surface 61b of the substrate 61. Therefore, the second
principal surface 61b is in close contact with the spiral wiring
21. As a result, since no other constituent element such as the
insulating layer 15 is interposed between the spiral wiring 21 and
the second principal surface 61b of the substrate 61, the
characteristics such as L and Rdc can be improved in the same
volume or the height can be reduced while maintaining the same
characteristics.
[0127] In this embodiment, the second magnetic layer 12 is also
directly disposed on the second principal surface 61b of the
substrate 61 including the spiral wiring 21. Therefore, the spiral
wiring 21 is in close contact with the second magnetic layer 12. As
a result, since no other constituent element such as the insulating
layer 15 is interposed between the spiral wiring 21 and the second
magnetic layer 12, the characteristics such as L and Rdc can be
improved in the same volume or the height can be reduced while
maintaining the same characteristics.
[0128] Since the second magnetic layer 12 is in close contact with
the spiral wiring 21 without the insulating layer 15, the vertical
wirings 51, 52 do not include the via conductors 25 penetrating the
inside of the insulating layer 15. Therefore, the spiral wiring 21
is directly connected to the columnar wirings 31, 32 penetrating
the inside of the second magnetic layer 12. As a result, interfaces
can be reduced in the vertical wirings 51, 52, and connection
reliability can be improved. Since the via conductors 25 having a
cross-sectional area smaller than the columnar wirings 31, 32 are
not included, Rdc of the inductor component 1A can be reduced.
Third Embodiment
[0129] FIG. 5A is a transparent perspective view showing a third
embodiment of an inductor component. FIG. 5B is a cross-sectional
view taken along a line X-X of FIG. 5A. The third embodiment is
different from the first embodiment in the configuration of the
spiral wiring. This different configuration will hereinafter be
described. In the third embodiment, the same constituent elements
as the first embodiment are denoted by the same reference numerals
as the first embodiment and therefore will not be described.
[0130] As shown in FIGS. 5A and 5B, in an inductor component 1B
according to the third embodiment, as compared to the inductor
component 1 of the first embodiment, multiple spiral wirings 21, 22
are arranged in the lamination direction, and the multiple spiral
wirings 21, 22 are connected in series.
[0131] Specifically, the first spiral wiring 21 and the second
spiral wiring 22 are laminated in the Z direction. The first spiral
wiring 21 is spirally wound in a clockwise direction from the outer
circumferential end 21b toward the inner circumferential end 21a
when viewed from the upper side. The second spiral wiring 22 is
spirally wound in a clockwise direction from an inner
circumferential end 22a toward an outer circumferential end 22b
when viewed from the upper side.
[0132] The outer circumferential end 21b of the first spiral wiring
21 is connected to the first external terminal 41 through the first
vertical wiring 51 (the via conductor 25 and the first columnar
wiring 31) on the upper side of the outer circumferential end 21b.
The inner circumferential end 21a of the first spiral wiring 21 is
connected to the inner circumferential end 22a of the second spiral
wiring 22 through the second via conductor 27 on the lower side of
the inner circumferential end 21a.
[0133] The outer circumferential end 22b of the second spiral
wiring 22 is connected to the second external terminal 42 through
the second vertical wiring 52 (via conductors 25, 26 and the second
columnar wiring 32) on the upper side of the outer circumferential
end 22b. Although not shown, the via conductor 26 extends in the Z
direction from the via conductor 25 on the upper side of the outer
circumferential end 22b of the second spiral wiring 22 and
penetrates the inside of the insulating layer 15. The via conductor
26 is formed on the same plane as the first spiral wiring 21.
[0134] Since the inductor component 1B has the first spiral wiring
21 and the second spiral wiring 22 connected in series, the number
of turns can be increased to improve L. Since the first spiral
wiring 21 and the second spiral wiring 22 are laminated in the
normal direction with each other, an area, i.e., a mounting area,
of the inductor component 1B viewed in the Z direction can be
reduced with respect to the number of turns, so that the inductor
component 1B can be reduced in size.
[0135] Although the inductor component 1B has a configuration
including two layers of the spiral wirings connected in series, the
present disclosure is not limited thereto, and the component may
have three or more layers of the spiral wirings connected in
series. Although the inductor component 1B has one inductor made up
of two layers of the spiral wirings and disposed on the same plane,
the component may have two or more inductors disposed on the same
plane.
Fourth Embodiment
[0136] FIG. 6A is a transparent perspective view showing a fourth
embodiment of an inductor component. FIG. 6B is a cross-sectional
view taken along a line X-X of FIG. 6A. The fourth embodiment is
different from the first embodiment in the configuration of the
spiral wiring. This different configuration will hereinafter be
described. In the fourth embodiment, the same constituent elements
as the first embodiment are denoted by the same reference numerals
as the other embodiments and therefore will not be described.
[0137] As shown in FIGS. 6A and 6B, in an inductor component 1C of
the fourth embodiment, as compared to the inductor component 1 of
the first embodiment, a plurality of spiral wirings 21C to 24C is
disposed on the same plane. The first spiral wiring 21C, the second
spiral wiring 22C, the third spiral wiring 23C, and the fourth
spiral wiring 24C have a semi-elliptical arc shape when viewed in
the Z direction. Therefore, each of the first to fourth spiral
wirings 21C to 24C is a curved wiring wound around about a half of
the circumference. The spiral wirings 21C to 24C each include a
linear part in a middle portion.
[0138] The first and fourth spiral wirings 21C, 24C each have both
ends connected to the first vertical wiring 51 and the second
vertical wiring 52 located on the outer side and have a curved
shape drawing an arc from the first vertical wiring 51 and the
second vertical wiring 52 toward the center side of the inductor
component 1C. The second and third spiral wirings 22C, 23C each
have both ends connected to the first vertical wiring 51 and the
second vertical wiring 52 located on the inner side and have a
curved shape drawing an arc from the first vertical wiring 51 and
the second vertical wiring 52 toward an edge side of the inductor
component 1C.
[0139] It is assumed that an inner diameter portion of each of the
first to fourth spiral wirings 21C to 24C is defined as an area
surrounded by the curve drawn by the spiral wirings 21C to 24C and
the straight line connecting both ends of the spiral wirings 21C to
24C. In this case, none of the spiral wirings 21C to 24C have the
inner diameter portions overlapping with each other when viewed in
the Z direction.
[0140] On the other hand, the first and second spiral wirings 21C,
22C are close to each other. Therefore, the magnetic flux generated
in the first spiral wiring 21C goes around the adjacent second
spiral wiring 22C, and the magnetic flux generated in the second
spiral wiring 22C goes around the adjacent first spiral wiring 21C.
The same applies to the third and fourth spiral wirings 23C, 24C
arranged close to each other. Thus, the first spiral wiring 21C and
the second spiral wiring 22C as well as the third spiral wiring 23C
and the fourth spiral wiring 24C are respectively magnetically
coupled.
[0141] When currents flow simultaneously through the first and
second spiral wirings 21C, 22C from the ends on the same side to
the other ends on the opposite side, the magnetic fluxes strengthen
each other. This means that when the ends on the same side of the
first spiral wiring 21C and the second spiral wiring 22C are both
used as the input side of pulse signals and the other ends on the
opposite side are both used as the output side of the pulse
signals, the first spiral wiring 21C and the second spiral wiring
22C are positively coupled. On the other hand, for example, when
one of the first spiral wiring 21C and the second spiral wiring 22C
has one end side used for input and the other end side used for
output while the other spiral wiring has one end side used for
output and the other end side used for input, the first spiral
wiring 21C and the second spiral wiring 22C can be brought into a
negatively coupled state. The same applies to the third and fourth
spiral wirings 23C, 24C.
[0142] The first vertical wiring 51 connected to the one end sides
of the first to fourth spiral wirings 21C to 24C and the second
vertical wiring 52 connected to the other end sides of the first to
fourth spiral wirings 21C to 24C each penetrate the inside of the
second magnetic layer 12 and is exposed on the upper surface. The
first external terminal 41 is connected to the first vertical
wiring 51, and the second external terminal 42 is connected to the
second vertical wiring 52.
[0143] The first spiral wiring 21C and the second spiral wiring 22C
are integrally covered with the insulating layer 15 so that the
electrical insulation of the first spiral wiring 21C and the second
spiral wiring 22C is ensured. The third spiral wiring 23C and the
fourth spiral wiring 24C are integrally covered with the insulating
layer 15 so that the electrical insulation of the third spiral
wiring 23C and the fourth spiral wiring 24C is ensured.
[0144] The inductor component 1C has wirings further extending
toward the outside of the chip from the connecting positions of the
spiral wirings 21B to 24B for the vertical wirings 51, 52, and
these wirings are exposed to the outside of the chip. Therefore,
the spiral wirings 21C to 24C have exposed portions 200 exposed to
the outside from side surfaces parallel to the lamination direction
of the inductor component 1C.
[0145] The exposed portions 200 are connected to a power feeding
wiring when additional electrolytic plating is performed before
singulation after the metal film 65 is formed by electrolytic
plating in the method of manufacturing the inductor component 1
described above. Even after the seed layer 63 is removed,
additional electrolytic plating can easily be performed with the
power feeding wiring, and an inter-wiring distance can further be
narrowed between the spiral wirings made up of the seed layer 63
and the metal film 65. Specifically, in the inductor component 1C,
the inter-wiring distance between the first and second spiral
wirings 21C, 22C and the inter-wiring distance between the third
and fourth spiral wirings 23C, 24C can be narrowed by performing
the additional electrolytic plating, so that the magnetic coupling
can be enhanced.
[0146] Since the spiral wirings 21C to 24C have the exposed
portions 200, a resistance to electrostatic destruction can be
improved at the time of manufacturing. Specifically, in the method
of manufacturing the inductor component 1, the exposed portions 200
are connected to a plurality of inductor components through the
power feeding wiring before singulation. Therefore, even if static
electricity is applied to the wirings in this state, the static
electricity can be dispersed through the power feeding wiring and
discharged to the ground, so that the resistance to electrostatic
destruction can be improved.
[0147] Preferably, in the spiral wirings 21C to 24C, a thickness of
an exposed surface 200a of the exposed portion 200 is equal to or
less than the thickness of the spiral wirings 21C to 24C and is 45
.mu.m or more. As a result, since the thickness of the exposed
surface 200a is equal to or less than the thickness of the spiral
wirings 21C to 24C, the proportion of the magnetic layers 11, 12
can be increased, and L can be improved. Additionally, since the
thickness of the exposed surface 200a is 45 .mu.m or more,
occurrence of disconnection can be reduced.
[0148] Preferably, the exposed surface 200a is an oxide film. As a
result, a short circuit can be suppressed between the inductor
component 1C and an adjacent component.
[0149] In the first to third embodiments, the spiral wiring may be
provided with an exposed portion similar to the exposed portion 200
of the fourth embodiment.
Fifth Embodiment
[0150] FIG. 7A is a transparent perspective view showing a fifth
embodiment of an inductor component. FIG. 7B is a cross-sectional
view taken along a line X-X of FIG. 7A. The fifth embodiment is
different from the fourth embodiment in the configuration of the
insulating layer. This different configuration will hereinafter be
described. In the fifth embodiment, the same constituent elements
as the first embodiment are denoted by the same reference numerals
as the other embodiments and therefore will not be described.
[0151] As shown in FIGS. 7A and 7B, in the inductor component 1D of
the fifth embodiment, as compared to the inductor component 1C of
the fourth embodiment, the insulating layer 15 does not entirely
cover the circumferences of the spiral wirings 21C, 22C.
[0152] Specifically, the adjacent spiral wirings 21C, 22C have side
surfaces 210C, 220C facing each other. At least a portion of each
of the side surfaces 210C, 220C is in contact with the second
magnetic layer 12. As a result, since the second magnetic layer 12
can be increased in amount and the second magnetic layer 12
containing a relatively soft resin can be increased in proportion
to improve the stress absorbability of the inductor component 1D so
that the influence of thermal shock, external pressure, etc. can be
reduced, the reliability of the inductor component 1D can be
improved. Additionally, if the second magnetic layer 12 contains
the metal magnetic powder, the DC superimposition characteristics
of the inductor component 1D can be improved.
[0153] The insulating layer 15 is disposed between the adjacent
spiral wirings 21C, 22C. As a result, the insulation and voltage
resistance between the adjacent spiral wirings 21C, 22C are
improved. The insulating layer 15 is located at a minimum distance
portion between the adjacent spiral wirings 21C, 22C and is in
contact with portions of the side surfaces 210C, 220C. The
insulating layer 15 may not be in contact with the side surfaces
210C, 220C, and, for example, the side surface 210C, the second
magnetic layer 12, the insulating layer 15, the second magnetic
layer 12, and the side surface 220C may be arranged in this order
between the adjacent spiral wirings 21C, 22C.
[0154] The present disclosure is not limited to the embodiments
described above and may be changed in design without departing from
the spirit of the present disclosure. For example, respective
feature points of the first to fifth embodiments may variously be
combined.
[0155] In the second embodiment, the spiral wiring 21 is in close
contact with both the second principal surface 61b of the substrate
61 and the second magnetic layer 12; however, the present
disclosure is not limited thereto, and the spiral wiring 21 may be
in close contact with only the second principal surface 61b or only
the second magnetic layer 12, while the insulating layer 15 may be
interposed for the other portions. Furthermore, in the second
embodiment, the spiral wiring 21 is in close contact with the
second magnetic layer 12 on the side surface and the upper surface;
however, only one of the side and upper surfaces may be in close
contact, while the insulating layer 15 may be interposed for the
other surface, or the side surface or the upper surface may only
partially and not entirely be in close contact with the second
magnetic layer 12, while the insulating layer 15 may be interposed
for the other portion.
* * * * *